/*
 * Copyright (c) 2003-2008 jMonkeyEngine
 * All rights reserved.
 *
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 * modification, are permitted provided that the following conditions are
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 *
 * * Redistributions of source code must retain the above copyright
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 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
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 *
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 *   may be used to endorse or promote products derived from this software 
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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package com.jme.scene.lod;

import java.io.IOException;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import com.jme.renderer.Renderer;
import com.jme.scene.TexCoords;
import com.jme.scene.TriMesh;
import com.jme.util.export.InputCapsule;
import com.jme.util.export.JMEExporter;
import com.jme.util.export.JMEImporter;
import com.jme.util.export.OutputCapsule;
import com.jme.util.export.Savable;
import com.jme.util.geom.BufferUtils;

/**
 * <code>ClodMesh</code> originally ported from David Eberly's c++,
 * modifications and enhancements made from there. <br>
 * <br>
 * This class is an extention of TriMesh that allows the option of rendering a
 * trimesh at various degrees of accuracy.
 * 
 * @author Joshua Slack
 * @author Jack Lindamood (javadoc only)
 * @version $Id: ClodMesh.java,v 1.23 2006/05/11 19:39:34 nca Exp $
 */
public class ClodMesh extends TriMesh {
    private static final long serialVersionUID = 1L;
    int currentRecord, targetRecord;
    CollapseRecord[] records;

    /**
     * Empty Constructor to be used internally only.
     */
    public ClodMesh() {
    }

    /**
     * Creates a new ClodMesh without any information. It is assumed a call to
     * reconstruct and create will be called before this ClodMesh is used.
     * 
     * @param name
     *            The name of the ClodMesh.
     * @see #reconstruct(com.jme.math.Vector3f[], com.jme.math.Vector3f[],
     *      com.jme.renderer.ColorRGBA[], com.jme.math.Vector2f[], int[])
     * @see #create(com.jme.scene.lod.CollapseRecord[])
     */
    public ClodMesh(String name) {
        super(name);
    }

    /**
     * Creates a ClodMesh that is a duplicate of the given TriMesh's geometric
     * information. RenderState and Controller information is not used and
     * should be set manually if those are to be copied as well. The records
     * parameter defines how the ClodMesh should collapse vertices. If null is
     * given, records are generated by the ClodMesh automatically.
     * 
     * @param name
     *            The name of the ClodMesh.
     * @param data
     *            The TriMesh to copy information into for this mesh.
     * @param records
     *            The collapse record(s) this ClodMesh should use. These modify
     *            how the ClodMesh collapses vertexes.
     */
    public ClodMesh(String name, TriMesh data, CollapseRecord[] records) {

        this(name, BufferUtils.clone(data.getVertexBuffer()), 
                BufferUtils.clone(data.getNormalBuffer()), 
                BufferUtils.clone(data.getColorBuffer()),
                new TexCoords(BufferUtils.clone(data.getTextureCoords(0).coords)), 
                BufferUtils.clone(data.getIndexBuffer()), records);
    }

    /**
     * Creates a clod mesh with the given information. A null for records causes
     * the ClodMesh to generate its own records information.
     * 
     * @param name
     *            The name of the ClodMesh.
     * @param vertices
     *            The vertex information of this clod mesh.
     * @param normal
     *            The per vertex normal information of this clod mesh.
     * @param color
     *            The per vertex color information of this clod mesh.
     * @param coords
     *            The per vertex texture information of this clod mesh.
     * @param indices
     *            The index array of this TriMesh's triangles.
     * @param records
     *            The collapse record(s) this ClodMesh should use. These modify
     *            how the ClodMesh collapses vertexes.
     */
    public ClodMesh(String name, FloatBuffer vertices, FloatBuffer normal,
            FloatBuffer color, TexCoords coords, IntBuffer indices,
            CollapseRecord[] records) {

        super(name, vertices, normal, color, coords, indices);

        create(records);
    }

    /**
     * This function sets the records information for this ClodMesh. If non-null
     * is passed, then the ClodMesh uses the passed CollapseRecord(s) to
     * determine how the TriMesh's triangles should collapse. If null is passed,
     * then the collapse records are created automatically with ClodCreator. In
     * most cases, null will be passed.
     * 
     * @param records
     *            The records for this ClodMesh to use, or null if it should
     *            generate its own.
     * @see ClodCreator
     */
    public void create(CollapseRecord[] records) {

        targetRecord = 0;
        currentRecord = 0;

        if (records != null && records.length > 0) {
            this.records = records;
        } else {
            ClodCreator creator = new ClodCreator(this.getVertexBuffer(), this
                    .getNormalBuffer(), this.getColorBuffer(), this
                    .getTextureCoords(0).coords, this.getIndexBuffer());
            this.records = creator.getRecords();
            creator.removeAllTriangles();
            creator = null;
        }
        setTriangleQuantity(this.records[0].numbTriangles);
        setVertexCount(this.records[0].numbVerts);

        updateModelBound();

    }

    private void selectLevelOfDetail(Renderer r) {
        // Get target record. The function may be overridden by a derived
        // class to obtain a desired automated change in the target.
        int iTargetRecord = chooseTargetRecord(r);
        if (iTargetRecord == currentRecord) {
            return;
        }

        // collapse mesh (if necessary)
        int i, iC;
        while (currentRecord < iTargetRecord) {
            currentRecord++;

            // replace indices in connectivity array
            CollapseRecord rkRecord = records[currentRecord];
            for (i = 0; i < rkRecord.numbIndices; i++) {
                iC = rkRecord.indices[i];
                // if (! (indices[iC] == rkRecord.vertToThrow))throw new
                // AssertionError();
                getIndexBuffer().put(iC, rkRecord.vertToKeep);
            }

            // reduce vertex count (vertices are properly ordered)
            setVertexCount(rkRecord.numbVerts);

            // reduce triangle count (triangles are properly ordered)
            setTriangleQuantity(rkRecord.numbTriangles);
        }

        // expand mesh (if necessary)
        while (currentRecord > iTargetRecord) {
            // restore indices in connectivity array
            CollapseRecord rkRecord = records[currentRecord];
            for (i = 0; i < rkRecord.numbIndices; i++) {
                iC = rkRecord.indices[i];
                // if (! (indices[iC] == rkRecord.vertToKeep))throw new
                // AssertionError();
                getIndexBuffer().put(iC, rkRecord.vertToThrow);
            }

            currentRecord--;
            CollapseRecord rkPrevRecord = records[currentRecord];

            // increase vertex count (vertices are properly ordered)
            setVertexCount(rkPrevRecord.numbVerts);

            // increase triangle count (triangles are properly ordered)
            setTriangleQuantity(rkPrevRecord.numbTriangles);
        }
    }

    /**
     * Called during rendering. Should not be called directly.
     * 
     * @param r
     *            The renderer to draw this TriMesh with.
     */
    public void draw(Renderer r) {
        selectLevelOfDetail(r);
        super.draw(r);
    }

    /**
     * Returns the number of records this ClodMesh currently uses.
     * 
     * @return The current length of the records array.
     */
    public int getRecordQuantity() {
        return records.length;
    }

    /**
     * This function should not be called manually. It selects the correct
     * target record based on the renderer used. For a basic ClodMesh, simply
     * the currently set target record is used. The target record signals how to
     * collapse this mesh's triangle information.
     * 
     * @param r
     *            A renderer which aids in choosing the correct target record.
     * @return The integer position in the records array for the target collapse
     *         record.
     */
    public int chooseTargetRecord(Renderer r) {
        return targetRecord;
    }

    /**
     * Returns the currently set target record.
     * 
     * @return The currently set target record.
     */
    public int getTargetRecord() {
        return targetRecord;
    }

    /**
     * Returns the current collapse records array. This array is created in
     * create()
     * 
     * @return The current collapse records array.
     * @see #create(com.jme.scene.lod.CollapseRecord[])
     */
    public CollapseRecord[] getRecords() {
        return records;
    }

    /**
     * Sets the current target record to the target value. If less than 0 is
     * passed, 0 is used. If a value greater than the current records length is
     * passed, then the maximum records length value is used.
     * 
     * @param target
     *            The new target record to use.
     */
    public void setTargetRecord(int target) {
        targetRecord = target;
        if (targetRecord < 0)
            targetRecord = 0;
        else if (targetRecord > records.length - 1)
            targetRecord = records.length - 1;
    }

    /**
     * Sets the records this ClodMesh will use to collapse triangles.
     * 
     * @param records
     *            The new records information of this ClodMesh.
     */
    public void setRecords(CollapseRecord[] records) {
        this.records = records;
    }

    public void write(JMEExporter e) throws IOException {
        super.write(e);
        OutputCapsule capsule = e.getCapsule(this);
        capsule.write(records, "records", null);
        capsule.write(currentRecord, "currentRecord", 0);
        capsule.write(targetRecord, "targetRecord", 0);
    }

    public void read(JMEImporter e) throws IOException {
        super.read(e);
        InputCapsule capsule = e.getCapsule(this);
        Savable[] savs = capsule.readSavableArray("records", null);
        if (savs == null)
            records = null;
        else {
            records = new CollapseRecord[savs.length];
            for (int x = 0; x < savs.length; x++) {
                records[x] = (CollapseRecord) savs[x];
            }
        }

        currentRecord = capsule.readInt("currentRecord", 0);
        targetRecord = capsule.readInt("targetRecord", 0);

        if (records == null) {
            create(records);
        }
    }
}
